Service manual

STP 11-25R13-SM-TG
3 - 5
PERFORM PREVENTIVE MAINTENANCE OF A VIDEO RECORDER/REPRODUCER
113-575-3050
Conditions: In a tactical or garrison environment, given a VTR, video test signal generator (VTSG), audio
test signal generator (ATSG), color TV receiver (or color monitor, audio amplifier, and speakers),
waveform monitor (WFM), vectorscope, a known good VTR, cotton swabs, chamois cloth, pure isopropyl
alcohol, head cleaner (such as xylene), rubber cleaner or rejuvenator, spray contact cleaner, silicone
lubricant, glass cleaner or mild liquid detergent, cloth, electronic equipment tool kit, video alignment and
work tapes, bench stock, DD Form 314, DA Form 2404, DA Form 2407, DA Pam 738-750, and
manufacturers' manuals.
Standards: The standards are met when preventive maintenance is completed with the verification of
PLAYBACK, RECORD, and ELECTRONICS-TO-ELECTRONICS (E-E) functions indicating no
malfunctions.
Performance Steps
1. Turn OFF VTR power and disconnect the VTR plug from the AC power outlet.
2. Clean dust, dirt, and foreign debris from the VTR exterior with a cloth dampened with glass cleaner.
3. Check for physical damage, missing controls, broken switches, burned-out lamps, and other
discrepancies.
4. Remove the VTR cover and any shielding or circuit boards necessary to gain unobstructed access to
the tape path.
5. Clean the head drum assembly.
a. Clean the rotary heads by lightly pressing a chamois cloth dampened with pure isopropyl
alcohol or head cleaner against the drum and turning the drum slowly with the direction of the
drum rotation (clockwise). Do not move the chamois vertically across the head tips. Clean the
entire upper drum assembly until removing all deposits and smudges.
b. Clean the scanner groove on which the lower edge of the tape rides, using a chamois cloth
piece dampened with isopropyl alcohol or head cleaner.
NOTE: If necessary, wrap the chamois around a sharp, but relatively soft object (for example, the bare
end of a swab stick or a bamboo skewer) dipped in xylene to scrape oxide residue from the scanner
groove. This process improves off-tape radio frequency stability and tape interoperability.
c. Clean the brush and slip ring assemblies with swabs dampened with isopropyl alcohol; do not
damage the brushes or leave fabric debris on the assemblies.
6. Clean tape transport contact surfaces (stationary head assemblies, tape guides, tension regulator,
and capstan shaft) using a chamois cloth or swabs dampened with isopropyl alcohol. Remove
visible deposits, smears, and smudges.
7. Clean the pinch roller with swabs dampened with rubber cleaner.
NOTE: If using alcohol to clean rubber surfaces, dry quickly to prevent deterioration.
a. Frequently change swabs until removing all black residue. The pinch roller appears dull when
clean.
b. Replace an exceedingly worn or pitted pinch roller.
8. Check drive belts, motor pulleys, and pad assemblies for dry rot, slippage, and serviceability.
Replace as needed or clean with swabs dampened with isopropyl alcohol.
NOTE: If this VTR has an idler tire, clean it with swabs moistened with rubber cleaner until no more black
residue comes off. Clean the supply and take-up reels as well.
9. Clean dust buildup off photo interrupters or sensors.
10. Inspect mechanical levers for cracks and bends. Examine plastic or metal cams for excessive wear.